If you’re not familiar with pressure canning, please read this beginner’s guide to pressure canning before getting started. Some agencies are writing for experienced canners, that understand that you need to adjust the canning time for elevation. For more on this, check out this fascinating discussion between Arit Anderson and water expert Janet Manning on the BBC Gardeners’ World podcast. Plastic watering cans are much lighter than metal ones, making them easier to carry, especially when filled with water.

Canned water - Wikipedia Canned water - Wikipedia

Offering a large capacity in chalk or stone, this attractive galvanised steel can will help keep your plants healthy for years.Overall, a metal watering can is likely a better choice if you prioritise durability, stability, and aesthetics, and are willing to invest a bit more money.

Water: collecting, storing and re-using / RHS Gardening Water: collecting, storing and re-using / RHS Gardening

A year’s not a “magic” number where it suddenly goes bad, it’s actually slowly degrading from day one. Following the same times as for water bath canning would be more than sufficient, given the higher temperatures.I think I would try stirring first to incorporate some oxygen and if that doesn’t help then maybe try filtering. You could boil it for a little bit longer if you wish to evaporate some of the chlorine off or even let it sit at room temperature uncovered overnight.